1. Field of the Invention
The present invention relates to a recording material support which has superior surface smoothness and water resistance, to an efficient process for manufacturing the same, to a recording material using the same which is capable of forming an image with excellent image quality and gloss, and to process for image formation using the recording material.
2. Description of the Related Art
In the related art, in order to obtain high quality images, high surface smoothness and water resistance are required to supports for various recording materials such as an electrophotographic image-forming material, a thermosensitive color recording material, an ink-jet recording material, a sublimation transfer image-receiving material, a silver photographic photosensitive material and a heat transfer image-receiving material, and various studies have been performed therefor.
On the other hand, in commercial printing and high-class printing, offset printing is widely used, and coated paper, such as art paper and coat paper, is employed. This is because the surface of coated paper is very smooth, so ink transfer properties are good, image reproducibility is high, image gloss is high and color reproducibility is good.
However, the coating layer of coated paper contains a large amount of pigment, and has high hygroscopic properties. Therefore, if coated paper itself is used as an image-receiving sheet for electrophotography and the image is fixed with heat, steam within the coated paper expands by the heat, so blistering (swelling of the coating layer) occurs between the raw paper and the coating layer. If this happens, the image is ruined, and a fine image like a photograph cannot be obtained (e.g., Japanese Patent Application id-Open (JP-A) Nos. 04-212168 and 08-211645).
In the conventional coated paper, when image information such as faces, scenery, or the like is output as a photograph, there is also a problem of inferior gloss. Therefore, at present, coated paper is hardly ever used as an electrophotographic image-receiving sheet.
JP-A No. 05-173352 discloses electrophotographic image-receiving paper, which uses a specific sizing agent and sets a sizing degree (Stökigt sizing degree) of raw paper within a predetermined range. However, in this publication, the Stökigt sizing degree of the raw paper surface is as low as 10 seconds to 20 seconds, and no reference is made to a very large Stökigt sizing degree of 100 seconds or more.
JP-A No. 05-241366 discloses coated paper, which can be used as electrophotographic image-receiving paper, and uses raw paper having an Oken type smoothness of 35 seconds to 200 seconds. However, on the raw paper used here, a recording layer (toner image-receiving layer) contains a large amount of pigment. Therefore, problems such as streaks are often encountered when using the pigment-based coating layer, in particular when the Oken type smoothness is more than 200 seconds.
In JP-A No. 2000-235276, a thick electrophotographic recording sheet is disclosed having an Oken type smoothness of 70 seconds to 200 seconds. However, this publication also states that if the Oken type smoothness is 200 seconds or more, problems arises in paper feed such that none or several sheets are often fed at once.